An enteric tablet coating is a barrier applied to oral medication that controls the location in the digestive system where the active pharmaceutical components of the tablet are absorbed. Most enteric coatings work by presenting a surface that is stable at the highly acidic pH found in the stomach, but breaks down rapidly at a less acidic, relatively more basic pH in the small intestine. For example, they will not dissolve in the acidic juices of the stomach at about pH 3, but they will in the alkaline at about pH 7 to 9 environment present in the small intestine.
Drugs that have an irritant effect on the stomach, such as aspirin, can be coated with a substance that will dissolve only in the small intestine. Likewise, certain groups of azoles such as esomeprazole, omeprazole, and pantoprazole are acid-activated. For such types of drugs, enteric coating added to the formulation tends to avoid activation in the mouth and esophagus.
Recently, some companies have begun to utilize enteric coatings on fish oil capsules, such as omega-3 fatty acids supplements. The coating prevents the fish oil capsules from being digested in the stomach, which has been known to cause a fishy reflux or fish burps.
Sometimes the abbreviation “EC” is added beside the name of the drug to indicate that it has an enteric coating.
Over a period of time, the coating equipment and associated equipment, such as vessels, piping and the like, become heavily coated with such coating materials comprising polycarboxylic polymers such as acrylic-based polymers, fatty acids, waxes, shellac, plastics, and/or plant fibers. In particular, the coating material must be removed from the surfaces of the equipment in order that the equipment can perform its function effectively and efficiently. In addition, because the equipment is often used in the pharmaceutical and/or food industries, the cleaning operation itself must be effective to remove all of the coating material, and must be approved, for example, by the U.S. Food and Drug Administration, for use in the pharmaceutical and/or food industries. Such cleaning operations should also be cost effective.
Prior cleaning operations have involved manually scraping the acrylic-based polymer material from the process equipment.
U.S. Pat. No. 5,609,693 describes a method useful for removing an acrylic-based polymeric material located on a surface, for example, a surface of a piece of process equipment. The method includes contacting an acrylic-based polymeric material located on the surface of a piece of equipment with a composition containing at least about 20% by weight of water and an organic component containing at least one alkylene oxide group, preferably a plurality of alkylene oxide groups, per molecule in an amount effective to solubilize at least a portion of the acrylic-based polymeric material. One particularly useful solvent component described therein is triethylene glycol monoethyl ether sold by Olin under the trademark Poly-solve TE.
It is described in U.S. Pat. No. 5,609,693 that a process temperature for removing Eudragit L with a composition comprising triethylene glycol monoethyl ether requires a process temperature of about 90° C.
It is known that the acrylic polymeric based tablet coatings Eudragit L have about 10% hydrophilic groups compared to Eudragit RS 30D having about 5% by weight hydrophilic groups only. The drawback of the method described in U.S. Pat. No. 5,609,693 is that the process temperature of about 90° C. is high thus energy consuming and the cleaning performance with respect for removing residues of acrylic polymeric based tablet coatings being less hydrophilic is poor.
Other components such as 2-ethoxyethanol have a low flash point of about 44° C. A low flash point bears the danger of being flammable in a concentrated composition. Still yet other components such as ethylene glycol monobutyl ether has a flash point of about 67° C., a very strong pungent odor and is considered to be toxic. A strong pungent odor will be not accepted by the consumer.
One can see that there is a continuing need for providing an improved cleaning composition useful for removing acrylic based polymeric coating materials, such as acrylic-based polymeric tablet coatings, from vessels and other equipment employed in using such materials, that is effective at lower process temperatures, contains an active cleaning component having a high flash point above 70° C., is without a pungent smell, biodegradable and does not pose a risk to the health of the consumer.